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Lesions and Diseases of the Spinal Cord: Brown-Séquard Syndrome and Tabes Dorsalis

by Craig Canby, PhD
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    00:00 Welcome to this lecture on the spinal cord.

    00:06 Our first slide depicts a lesion of the spinal cord.

    00:10 This lesion is involving the dorsal columns/medial lemniscal system.

    00:18 The lesion at this level within the spinal cord is affecting the first order neurons as they ascend and this lesion then is ipsilateral and as a result to this lesion being on the ipsilateral side of the pathway, there will be an ipsilateral loss of function below this level of the lesion.

    00:41 The loss of function would involve the loss of fine touch, two-point discrimination, loss of pressure and vibration senses, as well as conscious proprioception as these are the normal functions that are conveyed by this ascending pathway.

    01:02 Here, you’re looking at a cross-section through the spinal cord.

    01:07 And the lesion is depicted over here in the shaded light green area.

    01:13 And so if we identify the lesion and the accompanying clinical features, the lesion that’s a hemisection of the spinal cord as you see here is referred to as Brown-Séquard Syndrome.

    01:27 Brown-Séquard Syndrome is gonna involve various aspects of the spinal cord, the dorsal columns would be involved in through here.

    01:38 So again, this will be ipsilateral loss of fine structure, two-point discrimination, vibration, pressure, and conscious proprioception at and below that particular level of the lesion.

    01:54 The spinothalamic tracts are also involved here and in this case, there will be a contralateral loss of pain and temperature 1-2 segments below the lesion, and the reason that the loss of pain and temperature is 1-2 segments below the lesion is due to Lissauer’s tract.

    02:22 Lissauer’s tract, when the neurons, or at this level are ascending a couple of levels, and so this is involving those levels that are below this particular level in the spinal cord.

    02:36 Lastly, the corticospinal tracts are involved.

    02:41 and at this particular level, there will be an ipsilateral paresis at and below the lesion.

    02:51 Here, we’re looking at a continuation of Brown-Séquard Syndrome.

    02:57 In addition, to what we saw in the previous slide, descending hypothalamics will be lesioned.

    03:05 And so we lose the descending hypothalamic output.

    03:08 And at this lesion is above spinal cord level T1.

    03:13 The loss of sympathetics will result in ipsilateral Horner’s Syndrome.

    03:19 So, miosis, anhidrosis, and ptosis would be the triad of symptoms associated classically with Horner’s Syndrome.

    03:34 Lower motor neurons would be involved here.

    03:37 They would be damaged in the dorsal grey horn area and as a result there will be flaccid paralysis at the level of the lesion.

    03:51 And as it’s shown here, with paralysis, loss of muscle tone, and just a general state of hypotonia.

    04:04 Here, we’re looking at again a cross-section of the spinal cord but this is a different lesion, or have a different set of clinical features.

    04:15 Here, the lesion is, in this area of the cord, the posterior part.

    04:23 So it’s involving the dorsal columns.

    04:25 This particular lesion is referred to as Tabes Dorsalis.

    04:32 And this disease is characterized by a slow degeneration, demyelination of nerves found primarily in these dorsal columns.

    04:43 So, you have the fasciculus gracilis and the fasciculus cuneatus ascending through this area of the spinal cord.

    04:54 What are the accompanying clinical features of tabes dorsalis? Individuals that have this lesion complain of intense pain.

    05:09 They complain of disturbed sensation.

    05:16 and then usual high step gait.

    05:22 There gait it is unsteady and they will exhibit a positive Romberg’s sign, which is demonstrated by a loss of balance when the patient has their eyes closed.

    05:40 And this will be due to a loss of proprioception.


    About the Lecture

    The lecture Lesions and Diseases of the Spinal Cord: Brown-Séquard Syndrome and Tabes Dorsalis by Craig Canby, PhD is from the course Spinal Cord.


    Included Quiz Questions

    1. Loss of fine touch and conscious proprioception below the level of lesion
    2. Loss of pain sensation below the level of the lesion
    3. Loss of vibration and two point discrimination, above the level of the lesion
    4. Loss of temperature sensation below the level of the lesion
    5. Motor deficits above the level of lesion
    1. Temperature sensation 1—2 segments below the level of the lesion
    2. Pain sensation 1—2 segments above the level of the lesion
    3. Motor deficits above the level of the lesion
    4. Fine touch sensation below the level of the lesion
    5. Crude touch sensation on both sides
    1. Spastic paralysis at the level of the lesion
    2. Ipsilateral Horner’s syndrome
    3. Contralateral loss of pain and temperature
    4. Ipsilateral loss of touch and vibration
    5. Ipsilateral paresis at and below the level of the lesion
    1. Demyelination of the nerves primarily found in the dorsal column
    2. Degeneration of white matter in the brain
    3. Hemisection of the Spinal cord
    4. Vitamin C deficiency
    5. Infection with Borrelia burgdorferi

    Author of lecture Lesions and Diseases of the Spinal Cord: Brown-Séquard Syndrome and Tabes Dorsalis

     Craig Canby, PhD

    Craig Canby, PhD


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